TOC in the View menu of IPython Notebook. Tested in 0.9.

custom.css

.ui-menu {
    width: 300px !important;
}

div.code_cell {
    page-break-after: always;
    page-break-inside: avoid;
}

.rendered_html h4 {
    margin: 0.95em 0em;
} 

custom.js

$([IPython.events]).on('notebook_loaded.Notebook', function(){
    var view_menu = $($('ul#menus > li > ul').get(2));

    var render_toc = function() {
        // remove existing toc render
        view_menu.find('.toc').remove();
        view_menu.append('<hr class="toc" />');

        IPython.notebook.get_cells().forEach(function(cell, cell_num) {
            if(cell.cell_type !== 'heading') return;
            var text = cell.get_text();
            if(cell.get_level() > 1) {
                text = '&#x2514;' + text;
            }
            for(var i=1; i<cell.get_level(); i++) {
                text = '&nbsp' + text;
            }
            var mi = $('<li class="toc"><a href="#">'+text+'</a></li>');
            view_menu.append(mi);
            mi.click(function() {
                console.log(cell_num);
                IPython.notebook.scroll_to_cell(cell_num, 250);
            });
        });
        view_menu.data('menu').refresh();
    };


    $([IPython.events]).on('selected_cell_type_changed.Notebook', function (event, data) {
        render_toc();
    });

    render_toc();

});